the tank is a 75 g. its an older tank that has been setup at another house for i would say 3years. i got the tank and emptied the water, rinsed the sub straight set it backup. its been 2 years now that i have had it.
it is a well planted tank and has a large piece of driftwood with more than enough fish. my question is, for the last 6 months i have noticed my PH has be slowly getting higher. all other parameters are fine. i use tap water and treat it with prime. out of the tap the water is 7.0 and has never been more than 7.2, and in the tank its 7.6 to 7.8. i have used some Ph down over several days and it came down to 7.2 but 24 hrs later it shot back to 7.6. I have ecocomplete and the old river rock as sub straight and i keep the nitrate level at 10 to 15 (the plants seem to like it better there) and i do a 40% water change every two weeks. any ideas whats doing this?
any help is appreciated. the local fish stores are no help. thanks in advance.

Curt

01-13-2011 10:22 PM

This is because water has whats called a rebound effect. Its usually best not to mess with ph unless its extreamly to high or to low. Its better to have a stable ph then to try and adjust it as it changes. To avoid the "rebound" effect I use API's Proper PH 7.0 because my tap water is very hard here in orlando at a 8.6 out of the tap! The nice thing about proper PH is it rebuffers the water so you avoid the rebound effect. I had to use a tiny bit more than they suggested on the bottle but I dont have to add any more unless I do a water change.

hammerhead

01-13-2011 10:39 PM

Quote:

Originally Posted by Curt
(Post 559288)

This is because water has whats called a rebound effect. Its usually best not to mess with ph unless its extreamly to high or to low. Its better to have a stable ph then to try and adjust it as it changes. To avoid the "rebound" effect I use API's Proper PH 7.0 because my tap water is very hard here in orlando at a 8.6 out of the tap! The nice thing about proper PH is it rebuffers the water so you avoid the rebound effect. I had to use a tiny bit more than they suggested on the bottle but I dont have to add any more unless I do a water change.

but is it normal for the ph in the tank to be higher than the tap water? and why?

Curt

01-13-2011 10:55 PM

Quote:

Originally Posted by hammerhead
(Post 559307)

but is it normal for the ph in the tank to be higher than the tap water? and why?

This could be due to something in the tank like wood or gravel etc crushed coral etc.